Diarrheal disease is the second leading cause of death among children under 5 years of age globally. We are specifically interested in the diarrheal disease cholera because of the devastating impact the disease has on at-risk populations and an emerging opportunity to leverage mobile technology to overcome fundamental clinical and scientific challenges we have faced for decades in the cholera field. Despite effective treatments and advances in provider education, cholera case fatality rates remain high. Conventional methods have been unable to overcome barriers to provide patients timely access to care and fully understand the disease at the level of the household. With the emergence of high rates of cell phone penetration in areas with significant cholera associated morbidity and mortality, we feel there are new opportunities for intervention. Our research challenge is to take an unconventional approach to develop a system using mobile technology to identify cases, improve access to care, and characterize the microbial flora early in the disease state. The application's specific aims are (i) develop a system to detect cholera patients early in disease using mobile technology, (ii) validate the detection system and clinical impact of the system in an interrupted time series study with a control group, and (iii) characterize the microbial flora of cholera stool during the early disease state. These aims will generate the following deliverables: We will show for the first time that mobile technology can be used to identify and provide ORS to diarrheal disease patients early in disease. We will show that mobile technology can be leveraged to decrease the incidence and severity of cases admitted to the hospital. Lastly, we will implement the system to characterize cholera stool using modern techniques early in disease for the first time, which may impact our fundamental understanding of correlates to disease progression and transmission.